1 medium leek, white and tender green parts only, very thinly sliced
1 teaspoon sherry vinegar
1 large garlic clove, minced
1 tablespoon fresh lemon juice
1/2 tablespoon Tabasco
2 dozen oysters on the half shell
In a skillet, melt 2 tablespoons of the butter. Add the leek and cook over moderate heat, stirring, until softened and lightly browned, 8 minutes. Stir in the vinegar, transfer to a bowl and let cool. Stir in the garlic, lemon juice and Tabasco. Soften the remaining 4 tablespoons of butter and combine thoroughly with the leek mixture. Season with salt.
Light a grill. Place a dollop of leek butter on each oyster. Grill the oysters over high heat until just cooked through and the butter is melted, about 1 minute. Serve right away.
The Tabasco-leek butter can be refrigerated for up to 3 days. Let soften before using.